25. Whenever I go to Beijing, ____ is quite frequent, I will go to visit the Great Wall.
----Have you known Professor Jackson in our department for a long time ? ----Yes, since he _____ the our university.
--- Something wrong with my headache .--- No wonder. You ___________ on the program for such a long time.
_______ two exams to worry about, I have to work really hard this weekend.
_______ you’ve got lots of homework to do, we won’t hold a party this weekend.
Nancy enjoyed herself so much ______she visited her friends in Sydney last year.